Nitroimidazoles Flashcards
Nitroimidazoles
Metronidazole
Tinidazole
Used for organisms that other drug classes miss; gut anaerobes, parasites in patient with diarrhea; mild C. diff colitis
Tinid like metronid but only approved for parasitic infections
These drugs do not have adequate activity against aerobic bacteria
Nitroimidazoles MOA
Anaerobic bacteria and Protozoa activate a part of the nitroimidazole molecule that forms free radicals- damages DNA and leads to cell death
Nitroimidazoles Spectrum
Good
Gram- and Gram+ anaerobes (including Bacteroides, Fusobacterium, Clostridium
Protozoa (including Trichomonas, Entamoeba, and Giardia
Moderate
H. pylori
Poor
Anything aerobic
Anaerobes that reside in the mouth (Peptostreptococcus, Actinomyces, Propionibacterium)
Nitroimidazoles Adverse Effects
GI
N/V/D
Metallic taste
Hepatitis and Pancreatitis are rare
Neurologic
Peripheral neuropathy- dose related and reversible
Confusion and seizures are very rare
Nitroimidazoles Important Facts
Metronid causes disulfiram like reaction with alcohol (due to inhibition of aldehyde dehydrogenase)
Significant inhibition of warfarin (warfarin dose reduction likely needed)
Metronid oral is ~100% bioavailable
No drug cheating concerns with cations
Resistance to C. diff is uncommon but treatment failure is not; can exist as antibiotic resistant spores and cause relapses at end of treatment
If moderate to severe disease or more than one relapse of mild disease, use oral Vanco or fidaxomicin
Affecting a patient’s normal GI flora (primarily anaerobic) can set patient up for colonization with nasty bugs (VRE,etc)
Nitroimidazoles Good For
Abdominal anaerobic infections (use second drugs for aerobes if necessary)
Vaginal Trichomoniasis
GI infections caused by susceptible Protozoa (Amebiasis, Giardiasis)
Mild to moderate C. diff
H. pylori GI ulcer disease (in combo with other antibacterials and acid suppressive drugs)
